1. Field of the Invention
The present invention relates to the field of liquid crystal displaying techniques, and in particular to a method and device for termination detection of optical alignment of liquid crystal material.
2. The Related Arts
As the information era progresses, the demand on display device increases. To meet the demand, many panel display device are rapidly developed, such as, liquid crystal display device (LCD), plasma display panel (PDP), and organic light-emitting diode (OLED).
Among the panel displays, the LCD is gradually replacing the cold cathode display device due to the advantages of light weight, small size and low energy-consumption. However, the early twisted nematic (TN) or super twisted nematic (STN) LCDs all have the problems of low contrast and poor view angle. As the demand on the display quality gets higher, the wide view angle displaying technique, such as, In Plan Switch (IPS), Vertically Alignment (VA), are gaining momentum in development.
IPS possesses good wide view angle displaying result. However, for better IPS display result, the demand on the friction process during manufacturing is also very high, which reduces the redundancy of the friction process, in particular, in mass production. Compared to IPS, VA wide view angle displaying technique does not require friction process during manufacturing, which shows certain competitive advantage.
At present, the liquid crystal doped with polymer monomer is often used. In subsequent process, through the double effect of the UV and electricity to realize optical alignment. This technique is called polymer stained vertical alignment (PSVA). The advantage of PSVA is that the result neither protrudes nor causes ITO slit on the color film side, which saves the cost of color film as well as improve the overall transmittance.
However, because the PSVA uses UV for alignment and UV radiates on the liquid crystal after passing layers of glass substrate and alignment film, the actual UV illumination on the liquid crystal is greatly affected by the substrate. During manufacturing, the control is achieved through controlling the time. However, in mass production, the individual substrate may vary, which renders the pure time control ineffectiveness due to insufficient or over alignment.